针对多工种交叉作业频繁、环境时常变化、场地狭窄、明火作业多的建筑工程施工现场,以疏散时间为目标函数建立其人员疏散时间模型,基于疏散时间模型以疏散时间最短为目的提出疏散路径优化模型,并利用修正的迪杰斯特拉(Dijkstra)算法求...针对多工种交叉作业频繁、环境时常变化、场地狭窄、明火作业多的建筑工程施工现场,以疏散时间为目标函数建立其人员疏散时间模型,基于疏散时间模型以疏散时间最短为目的提出疏散路径优化模型,并利用修正的迪杰斯特拉(Dijkstra)算法求解模型,同时结合BIM(building information model)4D模型和Anylogic软件以及某在建楼房案例对模型进行仿真模拟验证分析。由仿真模拟结果可知,疏散时间模型计算出的疏散时长与模拟疏散时长吻合度较高,使用经优化后的疏散路径疏散,能够在一定程度上较大幅度节约紧急情况下建筑工程施工现场劳务人员的疏散时间,提高施工阶段的安全管理效率,且在一定疏散人数范围内,优化程度随疏散人数增加而增长。展开更多
Strain-induced quantum dots (QDs) like island formations are demonstrated to effectively suppress pits/dislocation generation in high indium content (26.8%) InGaN active layers.In addition to the strain redistribution...Strain-induced quantum dots (QDs) like island formations are demonstrated to effectively suppress pits/dislocation generation in high indium content (26.8%) InGaN active layers.In addition to the strain redistribution in the QD-like islands,strain modulation on the InGaN active layers by using the GaN island capping is employed to form an increased surface potential barrier around the dislocation cores,which inhibits the carrier transport to the surrounding dislocations.Cathodoluminescence shows distinct double-peak emissions at 503nm and 444nm,corresponding to the In-rich QD-like emission and the normal quantum well emission,respectively.The QD-like emission becomes dominated in photoluminescence due to the carrier localization effect of In-rich InGaN QDs at relatively low “carrier injection current”.Accordingly,green emission may be enhanced by the following origins:(1) reduction in pits/dislocations density,(2) carrier localization and strain reduction in QDs,(3) strain modulation by GaN island capping,(4) enhanced light extraction with faceted GaN islands on the surface.展开更多
We discuss the realization of broadband wavelength detection by demonstrating the longest cutoff wavelength(λc=28.6μm)far-infrared GaAs/AIGaAs quantum well infrared photodetectors(QWIPs).The responsivity is comparab...We discuss the realization of broadband wavelength detection by demonstrating the longest cutoff wavelength(λc=28.6μm)far-infrared GaAs/AIGaAs quantum well infrared photodetectors(QWIPs).The responsivity is comparable to that of mid-infrared GaAs/AIGaAs and InGaAs/GaAs QWIPs,with a responsivity of 0.265 A/W and detectivity of 3.4x109 cm.Hz1/2/W at the peak wavelength of 26.9μm at 4.2K.Based on the temperature-dependent dark current and response results,it is expected that similar performance can be obtained at least up to 20 K.Several ways to expand the wavelength coverage are also addressed.展开更多
文摘针对多工种交叉作业频繁、环境时常变化、场地狭窄、明火作业多的建筑工程施工现场,以疏散时间为目标函数建立其人员疏散时间模型,基于疏散时间模型以疏散时间最短为目的提出疏散路径优化模型,并利用修正的迪杰斯特拉(Dijkstra)算法求解模型,同时结合BIM(building information model)4D模型和Anylogic软件以及某在建楼房案例对模型进行仿真模拟验证分析。由仿真模拟结果可知,疏散时间模型计算出的疏散时长与模拟疏散时长吻合度较高,使用经优化后的疏散路径疏散,能够在一定程度上较大幅度节约紧急情况下建筑工程施工现场劳务人员的疏散时间,提高施工阶段的安全管理效率,且在一定疏散人数范围内,优化程度随疏散人数增加而增长。
基金Supported by the National Natural Science Foundation of China under Grant Nos 60876008 and 61076091the Program for New Century Excellent Talents in Fujian Province University.
文摘Strain-induced quantum dots (QDs) like island formations are demonstrated to effectively suppress pits/dislocation generation in high indium content (26.8%) InGaN active layers.In addition to the strain redistribution in the QD-like islands,strain modulation on the InGaN active layers by using the GaN island capping is employed to form an increased surface potential barrier around the dislocation cores,which inhibits the carrier transport to the surrounding dislocations.Cathodoluminescence shows distinct double-peak emissions at 503nm and 444nm,corresponding to the In-rich QD-like emission and the normal quantum well emission,respectively.The QD-like emission becomes dominated in photoluminescence due to the carrier localization effect of In-rich InGaN QDs at relatively low “carrier injection current”.Accordingly,green emission may be enhanced by the following origins:(1) reduction in pits/dislocations density,(2) carrier localization and strain reduction in QDs,(3) strain modulation by GaN island capping,(4) enhanced light extraction with faceted GaN islands on the surface.
基金Supported in part by the National Natural Science Foundation of China,QMX,TRAPOYT,and CKSP.
文摘We discuss the realization of broadband wavelength detection by demonstrating the longest cutoff wavelength(λc=28.6μm)far-infrared GaAs/AIGaAs quantum well infrared photodetectors(QWIPs).The responsivity is comparable to that of mid-infrared GaAs/AIGaAs and InGaAs/GaAs QWIPs,with a responsivity of 0.265 A/W and detectivity of 3.4x109 cm.Hz1/2/W at the peak wavelength of 26.9μm at 4.2K.Based on the temperature-dependent dark current and response results,it is expected that similar performance can be obtained at least up to 20 K.Several ways to expand the wavelength coverage are also addressed.